# Tau decays into two mesons: an overview

## TL;DR

This paper reviews theoretical approaches to tau decays into two mesons and a neutrino, focusing on form factors modeled with Chiral Perturbation Theory and dispersion relations, and extracting resonance parameters.

## Contribution

It provides a comprehensive overview of the current theoretical methods for analyzing tau decays into mesons, including resonance parameter extraction and form factor determination.

## Key findings

- Resonance parameters are extracted via pole positions in the complex plane.
- Form factors are described using Chiral Perturbation Theory with resonances.
- Low-energy observables related to the form factors are determined.

## Abstract

We review the state-of-the-art theoretical analyses of tau decays into a pair of mesons and a neutrino. The participant vector and scalar form factors, $f_{+}(s)$ and $f_{0}(s)$, are described in the frame of Chiral Perturbation Theory with resonances supplemented by dispersion relations, and the physical parameters of the intermediate resonances produced in the decay are extracted through the pole position of $f_{+,0}(s)$ in the complex plane. As a side result, we also determine the low-energy observables associated to the form factors. We hope our study to be of interest for present and future experimental analyses of these decays.